1. Field of the Invention
The present invention relates to a process for conditioning an anti-bacterial composition, so as to prevent its degradation during storage between manufacture and use. It also relates to an anti-bacterial composition conditioned according to the process.
The anti-bacterial composition to be conditioned according to the process comprising a portion of the present invention, contains lactoperoxidase, thiocyanate, a free oxygen donor and optionally lactoferrin.
2. Description of the Prior Art
It is known that the presence of thiocyanate, free oxygen and lactoperoxidase in an aqueous medium produces a bacterial inhibitor in the form of a monovalent hypothiocyanate ion (OSCN) in acid-base equilibrium with its acid form (HOSCN). (See for example EP No. 0 133 736).
The presence of water is thus necessary to trigger the above-identified reaction. Consequently, the storage of these mixed products can cause degradation. The degree of degradation is a function of the duration of storage, and also of the humidity of the medium.
In patent EP No. 0 133 736, one attempts to overcome this difficulty, either by using a non-aqueous medium, for example glycerine or propylene glycol, or by limiting the quantity of water in the composition (10% maximum by weight). The same patent also teaches the use of silica gel in the composition in the amount of 1 to 5% by weight, for trapping free water in the medium.
In GB No. 2162063, one attempts to overcome this difficulty (without specifically referring to it) by dispersing active materials in a large mass of dry powder. This helps to minimize the chance of active particles encountering each other, first to give off, assuming that the degree of humidity is not 0, hydrogen peroxide and then produce the ions (OSCN) in equilibrium with their acid form (HOSCN).
Once the medium is made aqueous, the mobility of these particles increases by reason of the great quantity of water which facilitates and/or participates, at the same time, in the reaction. The utilization of a large mass of dry powder as a carrier for the active materials, makes the use of such a composition delicate particularly for home use.
In all cases, either for compositions described in EPO No. 133 736, or for those described in GB No. 2 162 063, the risk of degradation of the active materials is present.
It is also known from French patent No. 2 345 940 that the free oxygen donor can be covered by a protective layer whose material becomes permeable and/or dissolves in the basic medium in the intestines. An example of such material is cellulose acetophthalate. The purpose of such specific protection is protection against gastric acidity. The antibacterial composition claimed in this patent, is directed only to the intestines whose medium is basic. This composition cannot be used for treating other regions whose medium is neutral or acidic as for example the mouth, the eyes, the skin and the vagina.